The present invention relates to a novel form of sealing means for the joint between the outlet of a casting ladle, the type used to handle molten metal or the like, and the closure member for the outlet of the ladle and, more specifically, to a sealing member which can be prefabricated and packaged so as to facilitate its incorporation into a casting ladle.
As is well known, parts of the outlets of casting ladles and their closures that are exposed to the flow of molten metal, while made of sturdy, fire-resistant material, still require periodic replacement. Accordingly, attempts have been made in the past to simplify the exchange or substitution of worn parts of the closures for casting ladles as well as to improve the seals between the joints of the closures and the outlets of the ladles to which the closures are attached.
It is, of course, important to use closure members that are physically stable, as well as to form proper seals between the closure members and the outlet of the casting ladles since failure of any of these parts can result in spattering of the molten metal during its discharge from the casting ladle which is not only dangerous to persons working near the ladle, but also can result in increased production losses.
In order to simplify the substitution of new closure members on casting ladles, it has previously been proposed to employ a plug-type closure in combination with annular discs made of highly heat-resistant mineral wool as a sealer. Use of such a sealer provides the advantage that the seal could be prefabricated, thus reducing the down time that had previously been incurred with the use of mortar material, which required that the ladle be inactive until the mortar set completely.
However, seals of mineral wool, as well as other types, could only be used where the parts of the closure member and outlet of the casting ladle were physically clamped together by an auxiliary mechanism in order to obtain a tight seal at the joint between the closure member and ladle outlet. Moreover, seals of this type cannot also be used where the sealing material itself must serve as a connection or attaching means.
The present invention has for its object the provision of a prefabricated seal as described above which avoids the foregoing disadvantages by providing a sealing body having a rigid core which is coated with a plastic, i.e., still unhardened mortar material. With the arrangement of the present invention, the sealing member can be packaged in an air-tight container so as to preserve the flowability of the plastic mortar material whereby the sealing member can be ready for use without requiring the addition of other materials or parts to form an integral seal.
One of the advantages of using a plastic or flowable coating about the rigid core is that the flowable coating material will serve to smooth out any irregularities in the surfaces defining the joints when the elements are brought into contact with the sealing member. Moreover, the rigid core of the sealing member assures the provision of a stable form for the seal. This facilitates prefabrication of the seal in a desired form to fill a given joint configuration.
Of significant importance is the fact that the prefabricated seal of the present invention will function to fill the joints between the parts even while they are at an elevated temperature. In such circumstances, it is, of course, necessary to place the seal in position immediately prior to joining the closure member parts to the parts surrounding the outlet of the ladle so that premature solidification or setting of the mortar coating will not occur.
In a preferred embodiment where the seal is to be used about the outlet of a casting ladle, the rigid core is substantially in the form of a circular disc which may be flat or shaped to conform closely to the surfaces defining the joint.
Also, according to a preferred embodiment, the rigid core body is formed with indentations or holes which become filled with the plastic mortar coating and function as anchoring means to guarantee adhesion of the coating to the rigid core, as well as retard migration of the mortar coating.